The present application relates generally to variable speed drives. The application relates more specifically to a cooling member for a power semiconductor module in a variable speed drive.
Variable speed drives (VSDs) used for heating, ventilation, air-conditioning and refrigeration (HVAC&R) systems typically use metal, for example, copper, cooling members or cooling blocks for mounting and temperature regulation of insulated gate bipolar transistor (IGBT) semiconductor switches. Metal cooling blocks are expensive for use in VSDs due to high material and labor costs, such as with machining, associated with manufacturing the metal cooling blocks. VSDs may also use plastic cooling blocks for cooling, which reduce material costs, but do not reduce labor costs, since the plastic cooling blocks also require machining Injection molding processes have generally not been used due to large size and low volume of plastic cooling blocks. The size of a particular cooling block is determined by the number of components, for example, modules, which are to be mounted to the cooling block. A cooling block may be designed to mount any number of modules. Each module to be mounted to the cooling block requires multiple channels to be machined into the cooling block to form a tub. Thus, a single cooling block may have a plurality of tubs, depending on the number of modules to be mounted thereto. For example, a cooling block used in a VSD may have two to six tubs to receive corresponding modules based on the output requirements of the VSD.